This photo from the social networking site Orkut.com, shows a man who was identified by neighbors in Connecticut as Faisal Shahzad. Mr. Shahzad was arrested at a New York airport Monday as a part of the Times Square bomber investigation.

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New York

Now that law enforcement authorities have charged Faisal Shahzad, an American citizen born in Pakistan, in the attempted Times Square bomber plot, they will be racing to see if there are other people – in the US or in Pakistan – connected to the failed attack.

Media reports suggest that Pakistan made several arrests in connection with the Times Square plot, but US Attorney General Eric Holder said he could not confirm the report in a press conference Tuesday. He did, however, say Mr. Shahzad has admitted involvement and that the bombing attempt "was a terrorist plot."

The ongoing investigation will entail going through Shahzad’s computer, his phone records, and talking to informants who may have met with him as well as neighbors and acquaintances. Shahzad is also giving interrogators valuable information, Mr. Holder said Tuesday.

On Tuesday, New York Mayor Michael Bloomberg declined to answer questions about what he referred to as “an ongoing investigation.”

Mayor Bloomberg said that “the last I heard, there was only one person they were talking to, but who knows where that is going to lead.” And, the mayor added: “There is still plenty of work to do.”

Mr. Shahzad is expected to be arraigned in New York on Tuesday afternoon.

President Obama said Tuesday that the administration would be looking to determine “what if any connection this individual has to terrorist groups and it includes collecting critical intelligence as we work to disrupt any future attacks.”

How a 'multifaceted' investigation works

Michael Wildes, a former federal prosecutor, says that means the FBI’s Joint Terrorism Task Force is acting in concert with other intelligence services around the world, including the Pakistani Intelligence Service.

"Knowing who this person consorted with over the past year is significant,” says Mr. Wildes, who now practices immigration law in New York.

Any investigation of Shahzad is likely to involve a close look at his finances, says Joseph King, a professor of terrorism at John Jay College in New York and a former federal agent.

“You want to look at possible movement of currency to him via his bank statements,” says Mr. King. “His finances would have to be looked at every step.”

For example, MSNBC is reporting Shahzad’s house in Shelton, Conn., is in foreclosure. However, he allegedly paid $1,300 in cash for the vehicle that was left in Times Square, which carried a bomb that failed to explode. “Where did he get the money?” asks King.

Who was sitting next to him on flights?

King says the federal authorities will also be looking closely to see if any other travelers have listed Shahzad’s house as their destination on incoming immigration forms. In addition, he expects security officials to look at the list of passengers of every flight Shahzad has flown to and from Pakistan.

“You want to see who was sitting next to him,” says King. “It may be a guy from California who has no relationship to him, just purely coincidental,” he says. “But should we look at him, absolutely.”

There are also reports that the police found a pistol in Shahzad’s car parked at JFK airport. King says that also raises more questions. “He’s a US citizen, so he can legally own a weapon, but where did he get it?” he asks. “I would also go back to that gun shop and look to see who bought weapons the week before the week after,” he adds.

Even as the authorities raced to get more information on Shahzad, there were questions about how close he came to leaving New York. According to Bloomberg, Shahzad was already on an Emirates Air flight to Dubai that had pulled away from the gate at John F. Kennedy Airport on Monday night before being called back to the gate.

“Clearly the guy was on the plane and he shouldn’t have been,” said Bloomberg.

But Holder said Tuesday that he was tracking Shahzad throughout the day Monday and was never worried about losing him, though he declined to elaborate on why Shahzad was allowed on the plane.